The major problem of nuclear waste is what to do with it. In fact, one of the biggest (and perhaps the single biggest) expenses of the nuclear power industry could eventually be the storage of nuclear waste. Currently, low level radioactive nuclear wastes are mostly being stored in tens of thousands of 55-gallon radioactive waste drums, which require to be stored in a specific warehouse and inspected regularly for environmental safety before they can be buried in a permanent nuclear disposal. Conventionally, in most nuclear waste warehouse, radioactive waste drums are grouped in fours to be placed on a conveying pallet and used as a storage unit. Although storing nuclear waste in radioactive waste drums can temporarily ease the concern of nuclear pollution, the physical, chemical and radioactive characteristics of each radioactive waste drum must be measured and inspected at a regular basis so as to protect the environment.
Take the radioactive waste drums inspection procedure performed in Japan for instance, as the nuclear waste storage warehouse in Japan also treats four radioactive waste drums as a storage unit while place a storage unit, i.e. four tanks, on a pallet, one pallet is transported to an inspection station to be inspected while rotating the pallet for enable the four symmetrically-arranged radioactive waste drums to be fetched by a grabber crane at will smoothly.
Following the progress of nuclear waste management, the concept of treating four radioactive waste drums as a storage unit is challenged since it is not economical in space usage. However, if more than four radioactive waste drums are placed on a pallet, the conventional method for loading/unloading radioactive waste drums to be inspected by an inspection procedure can not perform smoothly since the more-than-four radioactive waste drums can not be placed on the pallet symmetrically such that the grabber crane can not fetch each and every tanks at will simply by the rotation of the pallet. In addition, the inspection efficiency of a conventional inspection procedure is poor since at each effort of transporting a pallet to an inspection station, there are only four radioactive waste drums available to be inspected.
Therefore, it is in need of an improved pallet loading/unloading method for radioactive waste drums that is capable of carrying more than four radioactive waste drums on a pallet while enabling each tank to be inspected smoothly.